This invention relates generally to paved surfaces, and more specifically, to compositions and methods for microsurfacing of paved surfaces.
One of the most versatile tools for road maintenance is microsurfacing. Microsurfacing is a polymer-modified cold-mix paving system that can remedy a broad range of pavement problems, for example, on streets, highways, and airfields. Similar to a slurry seal, known compositions for microsurfacing begin as a mixture of dense-graded aggregate, asphalt emulsion, water, and mineral fillers. While conventional slurry seal is used around the world as an economical treatment for sealing and extending the service life of both urban and rural roads, microsurfacing has added capabilities, due to the use of high-quality, carefully monitored materials, including advanced polymers and other modern additives.
Originally, microsurfacing was developed for use in thicker applications, where it could be applied in narrow courses for wheel ruts, while not destroying the expensive road striping line. As scientists used highly selected aggregates and bitumen, and then incorporated special polymers and emulsifiers that allowed the product to remain stable even when applied in multi-stone thicknesses, the microsurfacing compositions resulted. Microsurfacing now is recognized not only as the most cost-effective way to treat the surface wheel-rutting problem, but also a variety of other road surface problems.
Known microsurfacing compositions are made and applied to existing pavements by a specialist machine, which carries all components, mixes them on site, and spreads the mixture onto the road surface.
As used herein, the term “L.A.”, refers to an amount of fine material dislodged from a coarse aggregate during the impact phase of a test used to determine the abrasion resistance of the coarse aggregate to impact in a rotating cylinder containing metallic spheres. L.A. is reported in terms of percent loss and the test method is sometimes referred to as the Los Angeles Rattler Test.